im sorry but this is a really dumb analysis, you used a single week of data to come to this conclusion.
Vgchartz numbers
2016
US-13.1m
EU-12.6m
2015
US-15.5m
EU-13.8m
2014
US-16.1
EU-15.6
2013
US-16.9m
EU-15.2m
2012
US-19.7m
EU-17.9m
2011
US-26m
EU-23.5m
2010
US-29.4m
EU-23.7m
2009
US-30.8m
EU-27.1m
2008
US-32.1m
EU-31.7m
Not a single year of EU being over US but its been consistently within 10%.
When the herd loses its way, the shepard must kill the bull that leads them astray.